1996 Auto Hard Shifts when cold

[ejbeach]

I recently bought a 96 XLT 4.0, it runs and drives great but when it's cold it shifts really hard. Once it warms up its smooth as can be.

Made an appointment to get it checked and they said the filter might be clogged.

They suggested a tranny flush, however, I was told by someone that flushing them with high milage is asking for problems? I was hoping to get some input from anyone who may have done this.

It has 134,000 miles on it, but seems to me to be well maintained. I know the previous owner used synthetic oil but I am not sure as far as transmission maintenance.

 

[carolinaboy]

I'm having the same problem with mine, same year/model but 106k miles. I had the transmission flushed at 103k because it was slipping, but it's still shifting hard until it warms up. Maybe it'll help yours, but if you find out what the problem is let me know.

 

[Glacier991]

The fact that is only does it when cold is strongly suggestive of something that moves ok when warm and not so good when cold... of the list of possibles in that category two things come quickly to mind... both being "boost valves" in that trannie.. the Electronic Pressure Control (EPC) boost valve (bore 207 for the FORD guys) or the pressure boost valve/main regulator valve (bore 208). That being my first guess (stuck, sticky etc) it COULD also be the TCC or EPC solenoid being stuck or sticky. Any of the above could cause higher than normal hydraulic pressures to be applied when the transmission shifts, causing harsh shifts.

There ARE other possible contingent diagnoses, including computer inputs being bad, etc, but I'd bet my money on those I first listed. The cure ? In my mind anyway... VB rebuild and maybe replace the TCC and EPC solenoids.

How to check ? Monitor the line and EPC pressure taps with a pressure gauge.